Scraper profiles conforming to this type are used, for example, in systems with which a watery substance, for example (partially dewatered) sludge, is guided along a screen surface with the assistance of scraper elements, through which screen surface any liquid that is still present is driven out of the substance. Thereby, the scraper profiles are attached to the scraper elements and form the transition to the screen surface. If the scraper elements move along the screen surface, the scraper profiles ensure that the substance to be dewatered is directed on the screen surface and thereby comes into contact with new areas of the screen surface. For this purpose, the scraper profiles usually have the specified longitudinal extension; that is, its length is a multiple of its width and/or height.
Thereby, it is possible to, among other things, attach the scraper profiles peripherally in a circumferential groove of a worm shaft, which moves in a cylindrical screen surface. In turn, corresponding worm shafts are used in the aforementioned dewatering devices, with which sludge is moved, with the assistance of the worm shaft, along a cylindrical screen surface surrounding the worm shaft, is thereby pressed and is thus dewatered.
With the known state of the art, it is disadvantageous that the gap between the screen surface and the areas of the worm shaft that are opposite the screen surface and bear the scraper profiles are not always constant (for example, because the screen surface features a low unbalance). This gives rise to local stresses of the scraper profiles or a gap in certain spots between the screen surface and the adjacent scraper profiles. In turn, this has the consequence that either the scraper profiles are too heavily degraded, or the dewatering of sludge to be dewatered is unsatisfactory.